Draft gears



2 Sheets-Sheet 1 DRAFT GEARS E. H. BLATTNER Aug. 4, 1959 Filed Oct. 21, 1955 451457" a) PERCENT COMPRESSION By his Attorney n w m n mt mm B 1 H e. 1 H 2 .m a E I F r 3 3 n 5 i H c H N m H m H L l E H m m m m R 1 A l E u G F o 0 m m m m 822: no 25305 2. 33

Aug. 4, 1959 E. H. BLATTNER DRAFT GEARS 2 Sheets-Sheet 2 Filed Oct. 21, 1955 Invento r:

Emil H. Blattner By @MM his Attorney 2,897,981 DRAFT GEARS Emil H. Blattner, Williamsville, N.Y., assignor to Symington Wayne Corporation, a corporation of Maryland Application October 21, 1955, Serial No. 542,013

7 Claims. (Cl. 213-45) This invention relates to draft gears for railway vehicles and particularly to draft gears employing rubber cushions, either alone or with other means for cushioning bufiing and draft forces.

An object of the present invention is to provide an improved draft gear wherein a rubber cushion is contained in a pocket of fixed maximum longitudinal dimension and divided into a plurality of parts by a floating follower, the rubber cushion being precompressed in situ through the floating follower as necessary to obtain the desired operating characteristics.

Another object of the invention is to provide a method of precompressing a rubber cushion in a pocket of fixed maximum longitudinal dimension in a draft gear wherein by first inserting part of the cushion along with a floating follower in the pocket, compressing that part between the follower and an opposing wall of the pocket, inserting another part of 'the cushion in the pocket on an opposite side of the follower'while holding the follower under compression and finally releasing the follower, the rubber cushion is enabled'to be precompressed in situ.

An additional object of the invention is to provide a' rubber cushion draft gear wherein the rubber cushion is housed in an open-sided pocket and-separated into a plurality of parts by a floating follower, each of the parts as a unit, and the floating follower being insertible through a side of the pocket and the rubber cushion through the floating follower being precompres sed in situ.

A further object of the invention is top'r ovide a rublarly pointed out in the appended claims, and be illus-- trated in the accompanying drawings, in which:

Figure-l is a plan view of a preferred embodiment of the draft gear of the present invention with portions broken away and shown in section to more clearly illustfatecertainiof the details of constnuction;

'FigureZ is a vertical sectional view of the gear of Figure l; V g

7 Figure 3' is a graph showing the loading characteristics of a typical rubber cushion over a part of its com- In as n-1 a e; and a ""Figu'res4-8 show by stages the method of precompressing the rubber cushion in situ.

Referring now in detail to the drawings, in which like reference characters designate like parts, the arrangement and method of the present invention, while applicable generally to rubber cushions for cushioning buffing and draft forces on railway vehicles, for purposes of illustration, have been applied to a simple but effec- U t d States: at m Patented Aug. 4, 1959";-

five draft gear of the housed type in which a rubber cushion constitutes the sole cushioning means. As shown in Figures 1 and 2, the exemplary form of draft gear is comprised of a one-piece, readily castable housing closed at one end by a rear or end wall 2 joining a pair of forwardly-extending, transversely or laterally spaced longitudinal walls 3 which may be either the top and bottom walls or the side walls of the housing. Unconnected for most of their length, the spaced longitudinal walls, adjacent their forward extremities, are joined at either side by a pair of laterally or transversely spaced side walls or webs 4, which with the longitudinal walls j substantially parallel confronting faces of the pair of longitudinal walls 3 and those of the end wall 2 and plunger 6, is a rubber cushion 9 which, typically, may be made up of a plurality of rubber spring elements 10.

alternating longitudinally with and separated by spaced or separating plates 11, each of the spring elements being formed of a center plate 12 carrying on either side a v plurality of annular rubber pads 13. In the conventional pocket, the rubber cushion is uninterupted. However, here,'it is divided or separated into a plurality of parts 1 by a floating follower block 14 of the same, preferably rectangular, cross-section as the plates of the rubber cushion and having on opposite sides integral guide lugs 15 riding or sliding in guide slots 16, one of which is formed in and extends longitudinally centrally of each of the longitudinal walls 3 of the housing.

With a draft gear of the above simple construction, a wide range of operating characteristics is obtainable by the method of the present invention for precompressing; Customarily, a

the rubber cushion in situ or place. rubber cushion is 'precompressed outside the pocket in which it will ultimately be installed and then inserted in-the pocket while being held under precompressionby This method not only is tedious but permits the clamp to be released only after the cushion has been inserted in its pocket, usually with some loss of the precompression due to encroachment Cclarnps or similar means.

upon the pocket by the clamps. The reason for such precompression is apparent from the graph of Figure 3'. A load of only about 27,000 pounds is required to compress a typical rubber cushion to some 27.27% of its total compression, while in the next less than 20% the, load increases to about 600,000 pounds and due to the sharp gradient of the curve increases with corresponding rapidity thereafter. The total travel permitted draft gears in the present standard A.A.R. draft gear pocket being but 2 /2 inches, a rubber cushion, unless preconipressed, obviously would be inadequate to cushion the longitudinal forces in bluif and draft to which the gear would be subjected in service.

In accordance with the method of the present invention, the necessity for compressing the rubbercushion outside its ultimate pocketandholding it. clamped during insertion is entirely avoided. Instead, one part of the rubber cushion, here that shown in Figure 6, is inserted uncompressed and, in the case of an open-sided housing, as a unit through a side of the pocket. Prior thereto, both the plunger 6 and the follower block 14 are inserted in the housing, both here through an open side of the pocket, and the follower block is held against 3 the plunger so as to afiord maximum space for the rub ber cushion. At this stage, with the first part of the cushion at free height substantially filling the pocket, the draft gear is placed under an hydraulic press and pressure is applied by the press ram indicated diagrammatically at 17, either directly on the follower block 14 or through: the plunger 6. This pressure or force in turn is transmitted by the follower block to the installed part of-therubber cushion to compress the latter from free height to the extent desired. The follower block then is held in compressing position by suitable means such as the illustrated blocks 18 which conveniently may be inserted in the guide slots: 16 forwardly of the guide lugs 15 ofthe follower block 14. On subsequent release of the applied force of the ram, the plunger 6 may be restored to initialposition and held there by suitable means such as the pins 19, leaving a space between it and the follower block 14. Into this space is inserted at free height the other part of the rubber cushion, as shown in Figure 8. Thereafter, it is only necessary to release the blocks 18, as by a temporary application of force to the plunger 6, to enable the follower block 14 to float between the two parts of the cushion and distribute the compression initially applied to the first part over the entire cushion. Consequently, it is not only possible by this method to precompress the rubber cushion in situ but, depending only on the amount of pressure applied to the first part of the cushion, the loading characteristics of the draft gear may be varied over a wide range, the draft gear at the upper limit of this range being enabled to absorb a loading far in excess of any now contemplated by the A.A.R.

From theabove detailed description it will be apparent that there has been provided an improved draft gear employing a rubber cushion precompressed in situ, as well as amethod of precompressing such cushions where-- by not only is a relatively simple and rugged draft gear enabled readily tomeet and exceed A.A.R. specifications, but a rubber cushion can be given any of a wide range of operating characteristics.

It will be understood that the described and disclosed embodiment is merely exemplary'of the invention and that all modifications are intended to be included which do not depart either from the spirit of the invention or the scope. of the appended claims.

Having described my invention, I claim:

1. A draft gear comprising a housing open atone end, a plunger in said open end and restricted in outward movement relative to said housing, a pocket in said housing intermediate a closedend thereof and said plunger, said pocket being restricted only on two opposite sides bysaid housing, a rubber cushion in saidpocket, and a floating follower block in said pocket and dividing said rubber cushion longitudinally into a plurality of parts.

2. A draft gear comprising a housing open at one end, aplunger in said open end and restricted in outward movement relative to said housing, a pocket in said housing intermediate a closed end thereof and said plunger, said pocket being restricted only on two opposite sides by said housing, a rubber cushion in said pocket, a floating follower block in said pocket and dividing said rubber cushion longitudinally into a plurality of parts, and guide means on said floating follower block and slidably engaging opposite longitudinal walls of said housing for guiding said follower block during longitudinal movement thereof relative to said housing.

. 3. A draft gear comprising a housing having a rear wall, a pair of transversely spaced forwardly extending 4v walls joined by said rear wall, a pair of spaced side webs connecting said longitudinal walls adjacent forward extremities thereof, said longitudinal walls being unconnected between said webs and rear wall, a plunger seated in an opening defined by said longitudinal walls and web and restricted in outward movement relative to said housing, a rubber cushion seated in a pocket in said housing defined by said rear and longitudinal walls and plunger, a floating follower block in said pocket and dividing said rubber cushion longitudinally into a plurality of parts, and guide means on said follower block and engaging said longitudinal walls for guiding said follower block during longitudinal movement. thereof relative to said housing.

4. A method of precompressing a rubber cushion of a draft gear comprising inserting into an open-sided pocket in said draft gear a floating follower block and a part ofsaid rubber cushion at free height, applying force to said follower block to compress said part between said follower block and an opposing wall of said pocket, holding said follower block in compressing position while inserting another part of said rubber cushion at free height in a space between said floating follower block and an end of said pocket opposite said opposing wall, and releasing said floating follower block to distribute. said force over said parts of said rubber cushion.

5. A method of precompressing a rubber cushion of a draft gear having an open-sided housing, comprising inserting into a pocket in said housing through an open side thereof a floating follower block and a part of said rubber cushion at free height, compressing said part between said follower block and an opposing wall of said pocket, holding said follower block in compressing position while inserting as a'unit another part of said cushion at free height through an open side of said housing into a space between said. follower block and an end of said' housing opposite said opposing wall, and releasing said floating follower block to. distribute said force over said parts of said cushion.

6. A draft tgear comprising a housing, a pocket in and opening onto an end of said housing, a rubber cushion contained in said. pocket, openings in and extend.-

ing longitudinally of said housing at opposite sides of said pocket, and a floating follower block in said pocket and projecting into said. openings, said follower block. dividing said rubber cushion longitudinally into a plurality of parts.

7. A draft gear comprising a, housing, a pocket inv and. opening. onto an end of said housing, a rubber cushion contained in said pocket, opening in and extending longitudinally of said housing at opposite sides of said pocket, a floating follower block in said pocket, and guide means on said follower block and projecting into said openings for guiding said follower block from longitudinal movement thereof relative to said housing, said follower block dividing said rubber cushion longitudinally into a plurality of parts.

References Cited in the file of this patent UNITED STATES PATENTS 1,853,857 Glascodine et a1 Apr. 12, 1932 2,540,334 Johnson Feb. 6, 1951 2,720,987 Blattner Oct. 18, 1955 2,808,945 Danielson Oct. 8, 1957 FOREIGN PATENTS 158,079 Australia Aug. 5,, 1954 

